mainly because a body of water above ground level would have to be traveling at the escape velocity of earth to stay up in the sky. and it would also have to be moving in a great circle around the earth, not a smaller one. all of the particles moving in this manner would generate enourmous friction, loose energy, and fall to earth.

so frankly, it just wouldn't happen. so if you think the bible is accurate then the interpretation should be that they meant clouds.

The model (or models) of the physical world represented in the Bible reflect the ideas of the people of the time and culture, which were far from accurate, from the point of view of modern science or even the more or less contemporary Greek thinkers.

I suppose the ancient Israelites imagined the Sun and other celestial bodies were either on the celestial dome (which supported the "waters above") or underneath it - sort of crawling on or hovering under the bottom of a giant aquarium. So the waters getting in the way of sunlight were not an issue.

AFAIK, a flat Earth was taken for granted.

Leszek. Pronounced [LEH-sheck]. The wondering Slav.
History teaches us that we don't learn from history.

For arguments sake, I was trying to visualize just one of the features - "waters above" the expanse, through which stars could be seen (in one interpretation).

Here are some effects I've thought about since yesterday:

1. Effect of light moving through water:
Light energy moves slightly slower through water, but it does move.
If the space between Sun and Earth was pure water, I think we would still get light.
Therefore, there may be no problem with light penetrating pure water in a canopy.

2. Effect of moving water:
When looking into a swimming pool that is perfectly still, there is one simple surface.
Standing at the side of the pool, you can see small objects at the bottom.
When the water is agitated with swimmers, there are many more surfaces with all kinds of angles.
From the same poolside point, it's impossible to see the same objects.
Therefore, I think the water canopy would have to be 100% still (having the properties of glass), for stars to be seen from Earth.

3. Cloud option:
A cloud (made of water drops, water droplets, ice crystals etc.) scatters light so much that it appears opaque.
Therefore, the Biblical canopy could not be a cloud; the sun moon, and stars were visible.

4. Effect of canopy as a lens:
The canopy would seem to be a meniscus lens (convex at upper surface, concave at lower surface).
From Earth, looking at objects directly above, there would seem to be no change.
Considering the relative close proximity to the underside of the canopy compared to Sun, I think the lens effect would be minimal. Imagine bacteria with eyes on the "eye" side of reading glasses, would not benefit from the lens design.

If the space between Sun and Earth was pure water, I think we would still get light.

False. Water absorbs light. After about 600 feet, almost all of the light is absorbed. After 3000 feet, there is no light from the surface at all. The average distance from the sun is approximately 92.75 million miles. That is slightly further than the 3000 feet needed to completely block out all light.

Therefore, there may be no problem with light penetrating pure water in a canopy.

Wrong for the reasons listed above.

Therefore, I think the water canopy would have to be 100% still (having the properties of glass), for stars to be seen from Earth.

True, it would have to be completely still in order to see through it. However that can't happen. If the water was above the Earth like you claim, it would have to be in orbit. In order for it to be in orbit It has to be moving at around 17,000 miles per hour. Slower than that and it falls to the ground. Water moving that fast would also likely heat up and boil off.

"He who fights with monsters should look to it that he himself does not become a monster...when you gaze long into the abyss the abyss also gazes into you" - Friedrich Nietzsche

Water absorbs light. After about 600 feet, almost all of the light is absorbed. After 3000 feet, there is no light from the surface at all.

Does that apply to pure water? Can you provide any references?

This talks about natural water (e.g. lakes and oceans):
"Water is transparent, meaning it allows light to pass through it.
The amount of light that penetrates the water depends on its `turbidity'
or the amount of dissolved minerals, silt and detritus material contained in it.
These particles cause light in water to be scattered and absorbed rather than transmitted."

Okay so I'll grant your position for the sake of argument that pure water will transmit light much further than non-pure water, which may be true. Although I still suspect over the course of 92.75 million miles there would be no sunlight reaching us. Even without my next point on contamination.

However, how long do you suppose that water would remain pure? The Earth is constantly taking on interstellar dust, comets burn up in the atmosphere etc. So assuming there was only the pure water canopy above us (and not 92.75 million miles of the stuff), which may or may not allow light through, depending on how think you want to claim it to be, pure or not. It would quickly become contaminated and thus transmit less and less light.
It would also be contaminated from below. Assuming it was touching the atmosphere it would slowly absorb foreign particles that way.

So even granting your premise that the water was pure and transmitted 100% of the light, it would over time absorb more and more light.

Now, through quick research, I have come the to conclusion that assuming all of the light was not scattered back out. The color of light you would get at the end of this canopy, would be blue. More information on that in the link below. So water does in fact absorb light, it simply does not absorb all light.